Well, I don't know if you call it an upgrade or an update or whatever, but Bloglines had some scheduled downtime last night while they moved to a new datacenter. From their news blog:

We look forward to vastly improved hardware capacity and tons of elbow room for growth.

This morning when I logged in, it definitely feels faster. There used to be a few seconds delay after clicking a feed and seeing the items. That delay is down to a second or less and is what you would definitely expect from a web app.